Two goals are set for the upcoming year. The first is further purification of the highly active and template-specific RNA dependent RNA polymerase that we have isolated from brome mosaic virus (BMV)-infected barley leaves. The second goal is to use a barley leaf protoplast system for detecting the synthesis of BMV-coded RNAs and proteins shortly after inoculation with BMV RNAs. Individual BMV RNA components and chemically-modified (including tyrosylated) BMV RNAs will be used for both the in vivo (protoplast) and in vitro (polymerase) assays. In particular, differences in the function of tyrosylated BMV RNAs as templates for transcription and translation will be compared with unmodified BMV RNAs.